Testicular microlithiasis

Testicular microlithiasis (TM) is a relatively common condition that represents the deposition of multiple tiny calcifications throughout both testes.

The most common criterion for diagnosis is that of five microcalcifications in one testicle, although definitions have varied in the past. In the majority of cases testicular microlithiasis is bilateral.

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Epidemiology

Testicular microlithiasis is seen in up to 0.6% of patients undergoing scrotal ultrasound. Some reports suggest that it may present in up to 5.6% of the general population between 17 and 35 years of age 3. Although testicular microlithiasis is present in ~50% of men with a germ cell tumor, it is very common in patients without cancer, and a direct relationship between the two has been debated.

Associations

Clinical presentation

Testicular microlithiasis per se is asymptomatic and is usually found incidentally when the scrotal content is examined with ultrasound, or found in association with symptomatic conditions.

Pathology

The microcalcifications are likely a marker of tubular degeneration, but not a risk factor for tubular degeneration 10.

Radiographic features

Ultrasound

Ultrasound is the modality of choice for examining the testes. Microlithiasis appears as small non-shadowing hyperechoic foci ranging in diameter from 1-3 mm. These foci occur within the testicular parenchyma and although usually distributed uniformly, may be distributed peripherally or segmentally 2.

One arbitrary grading system used on ultrasound is 13:

grade I: 5-10 microcalcifications

grade II: 11 to 20 microcalcifications

grade III: 21 to 30 microcalcifications

grade IV: >30 microcalcifications

It is unclear if a grading system adds prognostic value.

Treatment and prognosis

Testicular microlithiasis is in itself asymptomatic and benign. A relationship with testicular tumors, in particular germ cell tumors (GCT) is controversial. An ~8 fold increased risk of GCT in symptomatic testicles with microlithiasis has been reported (with microlithiasis found in approximately 50% of GCT cases), however, no increased risk has been found in asymptomatic testicles. It is also unclear whether early detection confers any benefit over self-exam. As such, screening is unlikely to be beneficial 1.

Some publications advise routine self-examination rather than sonographic surveillance 5 while others recommend annual ultrasound follow up when it is accompanied by other premalignant factors 6.

The European Society of Urogenital Radiology (ESUR) advises annual ultrasound follow-up until age 55, only if a risk factor is present 12 which include:

13. Richenberg J, Brejt N. Testicular microlithiasis: is there a need for surveillance in the absence of other risk factors?. European radiology. 22 (11): 2540-6. doi:10.1007/s00330-012-2520-4 - Pubmed